package com.atguigu.gulimall.product.service.impl;

import org.springframework.stereotype.Service;

import java.util.Collections;
import java.util.List;
import java.util.Map;
import java.util.stream.Collector;
import java.util.stream.Collectors;

import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.atguigu.common.utils.PageUtils;
import com.atguigu.common.utils.Query;

import com.atguigu.gulimall.product.dao.CategoryDao;
import com.atguigu.gulimall.product.entity.CategoryEntity;
import com.atguigu.gulimall.product.service.CategoryService;


@Service("categoryService")
public class CategoryServiceImpl extends ServiceImpl<CategoryDao, CategoryEntity> implements CategoryService {

    @Override
    public PageUtils queryPage(Map<String, Object> params) {
        IPage<CategoryEntity> page = this.page(
                new Query<CategoryEntity>().getPage(params),
                new QueryWrapper<CategoryEntity>()
        );

        return new PageUtils(page);
    }

    /**
     * 查询所有分类以及其子分类 以树形结构组装起来
     *
     * @return
     */
    @Override
    public List<CategoryEntity> listWithTree() {
        // 查出所有分类
        List<CategoryEntity> categoryEntityList = baseMapper.selectList(null);
        // 组成父子的树形结构
        // 找到所有一级分类
        List<CategoryEntity> level1Menus = categoryEntityList.stream().filter(categoryEntity ->
                        categoryEntity.getParentCid() == 0)
                .map((menu) -> {
                    // 将每个菜单的子分类填进去
                    menu.setChildren(getChildrens(menu, categoryEntityList));
                    return menu ;
                })
                .sorted((menu1, menu2)->{
                    return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
                })
                .collect(Collectors.toList());
        return level1Menus ;
    }

    /**
     * 递归查找所有菜单的子菜单
     * @param root
     * @param all
     * @return
     */
    private List<CategoryEntity> getChildrens(CategoryEntity root , List<CategoryEntity> all ) {
        List<CategoryEntity> children = all.stream().filter(categoryEntity -> {
                    return categoryEntity.getParentCid() == root.getCatId() ;
                })
                .map(categoryEntity -> {
                    // 递归寻找子菜单
                    categoryEntity.setChildren(getChildrens(categoryEntity, all));
                    return categoryEntity;
                })
                // 排序
                .sorted((menu1, menu2) -> {
                    return (menu1.getSort() == null ? 0 : menu1.getSort()) - (menu2.getSort() == null ? 0 : menu2.getSort());
                })
                .collect(Collectors.toList());
        return children ;
    }

}
